Signaling system or the like



Dec. 25, 1928. 1,696,544

N. HOLLAND SIGNALING SYSTEM OR THE LIKE Original Filed July 13. 1920 VENTOR ATTORNEY Patented 7 Dec. 25, 1928. v

UNITED STATES PATENT OFFICE;

NEWMAN H. HOLLAND, OF EAST ORANGE, NEW JERSEY, ASSIGNOR, BY IIESNE AS- SIGNMENTS, TO THOMAS A. EDISON, INCORPORATED, OF WEST ORANGE, NEW JERSEY, A CORPORATION OF NEW JERSEY.

SIGNALING SYSTEM OR THE LIKE.

Original application filed July 13, 1920, Serial No. 895,897. Divided and this application filed Kay 10,

1924. Serial No. 712,180.

My invention relates to signaling systems or the like and more particularly to railway signaling or-control systems wherein track circuits or other circuits containing or associated with relays or other control devices are employed to control signal circuits or signal control or other circuits; this application being a division of my copendingapplication, Serial No. 395,897, filed July 13', 1920, patented June 17, 1924, Number 1,498,238, and entitled Signaling systems.

In practically all railway signaling or control systems of this character now in use, the track or other control circuits are supplied either with direct current from primary or storage batteries, or with alternating current of given frequencies fed thereto from high voltage transmission lines by transformers. Where direct-current track circuits are used, there is more or less danger of failure of operation of the signal for a given track section, by reasonof the entrance of stray cur rents into the corresponding track circuit from outside sources. Where alternatingcurrent track circuits are employed, the same are, of course, immune to stray direct currents, but are likely to be seriously affected by stray alternating currents coming from sources wholly outside the system. This is due to the fact that the great majority of alternating-current circuits now used are supplied with commercial alternating currents at certain frequencies and alternating currents of the same frequencies are often used in alternating-current signaling or control systems. Moreover, the present-day types of alternating-current signaling or control systems, are of high initial cost and comparatively complex due to the necessity of using large central power houses usually provided with alternating-current generating apparatus in duplicate, substantially constructed high power transmission lines, transformers, impedance bonds, polarized circuits, line-control circuits, etc.

O ne-of the principal objects of my'invention is to rovide an improved, and an extremely simple and efficient signaling or control system which has all the advantages of present-day alternating-current railway signal or control systems as regards interference by stray or foreign direct currents, which will be unaffected by stray currents from alternating-current circuits supplied with commercial alternating currents, and wherein it is unnecessary to employ polarized circuits, or line-control circuits, or a transmission line for supplying current to the different track or control circuits.

Another and also one of the principal obj ects of my invention, is to provide a signalingor control systemofthis character wherein current variations such as direct-current pulsations or alternating currents are produced in the track circuits or the circuits containing or associated with the relays or control devices forcontrolling the signal circuits or signal-control or other circuits by means comprising a novel type of pulsating-current generator and suitable sources of direct current such as primary or storage batteries.

A further object of my invention resides in a novel form of relay especially adapted for use in my improved s stem..

More specifically escribed, my invention as applied to a railway signaling system,

- consists in producing in each track circuit of such a system, by the use of sources of direct current such as primary or storage batteries, current variations such as direct-current pulsations or alternating current, of a 'veri frequency and preferably different from the frequency of the current variations produced in any adjacent track circuit, and associating with each track circuit a relay or other control device'for controlling the corresponding signal or signal-control circuit and which is tuned to the frequency of the current variations produced in such track circuit. I preferably employ as the means for producing current variations in each track circuit, a direct-current circuit supplied with current from a primary battery or other suitable source and containing a resistance means such as a microphone, the resistance of which is variable by vibration, and vibratory means such as a reed and preferably a tuning fork positioned so as to affect such resistance means by its vibration whereby'direct-c'urrent pulsations of a definite period or frequency corresponding to the natural period of vibration of said reed will be produced in such direct-current circuit. The relay or other control device for controlling the corresponding signal circuit is tuned, preferably both mechanically and electrically, to the frequency of the current variations thus produced in the track circuit, and the arrange-' ment is preferably such that the frequency of the direct-current pulsations or the alternat ing current thus supplied to each track circuit is different from that supplied to any adjacent track circuit and also different from the frequencies of any stray currents such as the commercial alternating currents usually employed for the propulsion of railroad trains or other purposes.

Other features and objects of my invention will be hereinafter more fully described and claimed.

In order that my invention may bewmore clearly understood, attention is directed to the drawing accompanying and forming a part of this specification, and in which:

Figure 1 is a diagrammatic view illustrating a portion of one form of a railway signaling system in accordance with my invention, in which the current variations produced in the track circuits associated with the relays for controlling the signal circuits are direct-current pulsations, and in which the circuits containing or associated with the relays have produced therein alternating currents of fre- .variations produced in the latter circuits are direct-current pulsations; and

Figure 3 is a view similar to Figure 1, of a further modification in which the track circuits arexsupplied with alternating current.

Referring to the drawing and especially to Figure 1, reference characters A, B and C represent three track sections of a railway signaling system in accordance with my invention, and S the signal associated with and disposed at the entrance of the section B for governing the same; it being understood that similar signals are disposed at the entrance of all other sections of the system. Reference character M represents a rimary battery one side of which is connecte to one rail 1 of the section B at the exit end thereof by means of conductor 2, and the other side of which is connected to the rail 3 of section B at the exit end thereof through conductor 4, conductor 5, microphone 6 and conductor 7. The microphone 6 is mounted on a suitable support E on which is also mounted a vibratory reed such as a tuning fork 8. An electro-magnet 9 is disposed adjacent one leg of the tuning fork 8, and one end of the coil'of this electro-ma net is connected to one side of the battery through conductors 10 and 2, while the other end of said coil is connected to the other side 7 of the battery M through conductor 11, mi? crophone 12 and conductors 13 and 4. The microphone 12 is also mounted on the support E-and it will accordingly be apparent that both of the microphones 6 and 12 will be affected by vibrations of the tuning fork. At the entrance end of the section B, the rails 1 and 3 are respectively connected by means of conductors 14 and 15 to the prima 16 of a transformer, the secondary 17 of t e transformer being connected in circuit with the electro-magnet 18 of a relay. The armature of the relay consists of a vibratory reed, preferably a tuning fork 19, mounted on a suitable support F and having the same natural period of vibration as the tuning fork 8. ThlS tuning fork 19 controls a switch K which is located in a circuit to be controlled such as the signal or signal-control circuit for signal S, and which comprises two spring contacts 20 and 21 fixed atone end. The spring contact 20 comprises two arms 22 and 23, and normally assumes a position with its arm 22 engaging one leg of the tuning fork 19 and with its arm 23 in opposed spaced relation at its upper end to the upper end of the spring contact 21. Suitable means is provided for efi'ectin a relative adjustment of the contacts 20 and 21,'this means as shown consisting of a screw 24 threaded through a suitable support and 105 coacting with the contact 21 to effect adjustment of the upper end of the latter towards and away from the upper end of the arm 23 of the contact 20. Reference character N represents a suitable source of current such as a 1 primary or'storage battery for supplying current to the circuit to be controlled, such as the signal or signal-control circuit for signal S, one side of the battery being connected to a motor (not shown) disposed in the casing G, 115 for actuating the signal S, by means of conductor 25, and the other side thereof being connected to contact 20 of switch K by conductor 26. The signal actuating motor in ms ing G is also connected to switch contact 21 by 120 means of conductor 27. When the signal or signal-control circuit is opened, the signal actuating motor in casing G will, of course, cease to o crate and the signal S will thereupon, un er the action of gravity, drop to danger position as shown; but when this circuit is closed, the motor will move the signal S to and hold the same in clear position as indicated in dotted lines.

The operation of that form of my invention conductor 14 to the primary 16 of the trans-- former, then through conductor 15, rail 3, conductor 7, microphone 6, conductor 5 and conductor 4 back to the battery. Direct cur-" rent will also be continuously supplied to a second circuit over the following path: From the battery M through conductor 2, conductor 10, the coil of electro-magnet 9, conductor 11, microphone 12, conductor 13 and conductor 4 back to the battery. This second circuit together with the tuning fork 8 disposed in operative relation to the electro-magnet 9 comprisea' pulsating current generator, for when this circuit is made, the electro-magnet 9 attracts the tuning fork 8 and starts the same vibrating in its natural period, the tuning fork 8 in vibrating, vibrates the support E and microphone 12, thereby producing changes or variations in the resistance of the microphone 12 corresponding in frequency to the vibrations of the tuning fork which in turn effects current variations or pulsations in the circuit including the coil of electromagnet 9. It is therefore apparent that the tun ng fork will be continuously vibrated in its'natural period as long as said circuit is closed and supplied with current. The vibrations of the tunin fork 8 also effects variations of the same %requency in the resistance of the microphone 6, and accordingly directcurrent pulsations of a frequency corresponding to the frequency of the natural period of. vibration of the tuning fork 8 are produced in the track circuit including the primary 16 of the transformer. Of course, it is not necessary to connect the electro-magnet 9 and microphone 12 in shunt with the track circuit as shown, for the same results may be obtained by using a single microphone and connecting the same and the electro-magnet in series with the track circuit. Obviously alternating current of a frequency corresponding to the frequency of the direct-current pulsations in the track circuit, will be produced in the circuit of the secondary 17 of the transformer and the electro-magnet 18 of the relay controlling the signal or signal-control circuit. The relay is suitably electrically tuned to the frequency of the alternating current thus produced in the-circuit of the secondary 17 of the transformer and the electro-magnet 18, and, therefore, to the frequency of the direct-current pulsations in the track circuit and to the natural period of vibration of tuning fork 8, as by means of an adjustable con denser D in the circuit of the secondary 17. The tuning fork 19 comprising the armature of the relay, being of the same natural .period of vibration as the tuning fork 8, the relay is also mechanically tuned to the frequency of the alternating current in the circuit of the electro-magnet 18 and secondary 17 of the transformer and, therefore, to the frequency of the direct-current pulsations produced in the track circuit by the pulsating-current enerator. The tuning fork 19 thereore, assuming the sections B to be unoccupied, be vibrated in its natural period and, by reason of the engagement of one legth'ereof with the arm 22 of the spring contact 20, will normally maintain the latter in circuit closing position with the arm 23 thereof in engagement with the spring contact 21. In this connection it is to be noted that the spring contact 20 should have a natural period of vibration different from and preferably much less than the natural period of vibration of the tuning fork 19. Switch is thus being maintained closed, current will be supplied to the signal actuating motor and the signal S will be normally held in clear position asexplained above. When a train T moves into the section B, as shown, the primary 16 of the transformer will be short-circuited and accordingly the electromagnet 18 of the relay will be de-energized. The tuning fork 19 will thereupon cease to vibrate, the spring contact 20 of switch is Will move to and remain in open position, the motor in casing G will cease to operate and the signal S will, under the action of gravity, drop to danger position, as shown, When the train T moves out of the section B, the relay controlling the signal or signal-control circuit will again be operated as above described, said circuit will be closed and the signal returned to clear position.

Figure 2 illustrates a slight modification of the system shown in Figure 1 in which the relay for controlling a circuit such as the signal or signal-control circuit for signal S is only mechanically tuned to the direct-current pulsations produced in the track circuit instead of being both mechanically and electrically tuned thereto. In the system as shown in this figure, the rails 1 and 3 of section B, are directly connected at the entrance end of the section by means of conductors 14 and 15, respectivel 14 and 15 shown in Figure 1, to the coil of the electro-magnet 18 of the relay for controlling the signal or signal-control circuit instead of to the primary of a transformer. According corresponding to the conductors ly, direct-current pulsations of a frequency tion B is unoccupied, the electro-magnet 18' will be supplied with. direct-current pulsations and effect the vibration of the tuning fork 19 in its natural period. Except as just described, the construction, arrangement and operation of this form of my invention and that shown in Figure 1' are the same.

In the modification shown in Figure 3, the conductors 2' and 7, respectively corresponding to the conductors 2 and 7 of the system shown in Figure 1, instead of being respectively connected to the rails 1 and 3 of section B, are connected to the primary 29 of a transformer. The secondary 30 of this transformer is connected by conductors 31 and 32 across the rails 1 and 3 of the section B at the exit end thereof, and said rails are respectively connected at the entrance end of the section B by means of conductors 14 and to'the terminals of the coil of the electro-magnet '18 comprising a part of the'relay (the rest of the relay not being shown) for controlling the signal or signal-control-circuit. .In this system the track circuitisias follows: From one terminal of the secondary through conductor 31, rail 1, cond uctor 14", the coil of electro-magnet 18, conductor 15, rail 3 and conductor 32, to the other terminal of the secondary 30. It will be apparent that direct-current pulsations of a frequency corresponding to the frequency of the vibrations of the tuning fork 8 will be produced in the circuit of the primary 29 of the transformer, such circuit being as follows: From the battery M through conductor 2', primary 29,

iconductor I,'microphone 6, conductor 5 and conductor 4 back to the battery. Alternating current of a frequency corresponding to the frequency of the direct-current pulsations in the circuit of the primary 29 will therefore be produced in the track circuit including the secondary 30 of the transformer, and when the section B is unoccupied, the electro-magnet 18 of the relay will be energized, for the latter is suitably electricall tuned, as by means of the adjustable con enser I), to alternating current of such frequency. The relay 'will thereupon effect the closing of the signal or signal-control circuit for the signal for track section B and said signal will accordingly be moved to clear position.

-When a train T enters section B,'the electromagnet 18 will be short-circuited. whereupon the signal or signal-control circuit will be automatically opened and the signal will moveto danger position, as will be understood.

\Vhile with respect to each form of the invention disclosed herein, I have shown and described the circuit connections for only one tracksection, it is to beunderstood that similar circuit connections operating in a similar manner, are provided for all other sections. The arrangement is preferably such, however, that the pulsating-current generator associated with any section produces current pulsating-current generator associated with any adjacent section, whereby there will be no danger of the relay for any section being affected by stray currents from the'circuit connections of any adjacent section.

While I have shown several embodiments of my invention, it is to be understood that these are for the purposes of illustration only and that such embodiments are subject to numerous changes and modifications without departure from the spirit of the invention and the scope of the appended claims. It is also to be understood thatwhile I have shown my invention as applied to railway signaling systems, it is equally. well adapted, as to its principal features atleast, forapplication to various other. systems including automatic train-control systems. g Having now described my invention, what I claim as new and desire to protect by Let- {ers Patent of the United States, is as folows:

1.'In combination, a direct-current constantly closed circuit including theprimary of a transformer, a second circuit including the secondary ofthe transformer, and means for producing current pulsations of a given frequency in the direct-current circuit whereby an alternating current of the same frequency is produced in said second circuit; said means comprising a vibratory reed inde endent of said direct-current circuit and vibrated at its natural period and a microphone in said direct-current circuit, said microphone being in spaced relation to said reed so as not to be engaged by the latter in the vibration thereof, but being positioned so as to be affected by the vibrations of the reed, substantially as described.

2. In combination, a direct-current circuit including the primary ofa transformer, a second circuit including the secondary of the transformer, a tuning fork independent of said direct-current circuit, and a microphone included in said direct-current circuit, said microphone being in spaced relation to said tuning fork so as not to be enga ed by the same in the vibration thereof, but being positioned so as to be afiectedby vibration of said tuning fork, substantially as described.

3. A pulsating current generator, comprising a tuning fork, means including coil means for effecting vibration of said tuning fork, and a circuit including resistance means, the resistance of which is affected by vibrations, said resistance means being in spaced relation to said tuni fork so as not to be engaged by the latter in the vibration thereof, but being positioned so as to be affected by the vibrations of said tuning fork, substantially as described. I

4. A pulsating current generator, comprising a vibratory reed, means including coil means for efi'ectin vibration of said reed, being positioned so as to be affected by the and a circuit inclu ing resistance means the vibration of said reed, substantially as deresistance of which is affected by vibrations, scribed. 10 said reed being independent of said circuit This specification signed this 9th day of and said resistance means being in spaced May, 1924. relation to said reed so as not to'be engaged by the latter in the vibration thereof NEWMAN H. HOLLAND. 

